VGA to TV converter

Design and copyright by Tomi Engdahl

I keep all the rights to this circuit. You can freely build this circuits
for your own use but you are not allowed to use
those circuit designs commercially without written permission from the
designer.

NOTE: There is serious lack of DOS and Windows driver for this
circuit for most of currently available graphics cards.
The reason for this is the very fast changing graphics card
product maket and lack of resources to develop drivers
for each of them (even maker of some commercial operating systems have
problems in keeping up the speed of change, so this is completely
out of reach for a non-commercial few persons free time project).
I don't personally plan to develop any new drivers for this project.
I don't provide technical support for this through e-mail
(too many requests, lack of time and more interrest in this project).
Use the project as it is here or forget.
This project worked well with DOS with 100% VGA compatible graphics
cards on standard VGA modes and quite well with Linux with many cards.
If you get it working, use it (detailed success stories I can
put on-line wellcome). If you can't get it work then it's your problem,
I don't have time and interrests to sort out the problems with each
and every PC hardware that there exists (hundreds of different graphics
card models, many operating systems and dirfferent driver versions are
a mess I don't go anynymore to).

Please note that the circuit described below might have a very limited
use as a gaming device because the limitations of the driver support and
the fact that there is no flicker reduction filtering. The concept was quite
well working earlier (commercial products used same principles) but nowadays
many desent games will program the video card directly over writing
what the drivers so there are many games which does not work with this
circuit. The circuit described below has still value for for hardware experimentals
who wish to use the circuit for some special applications where they need only
few supported graphics modes and are willing to spend time on making this to work. Anyway getting the circuit to work is kind od gamble, because it
works perfetly with many graphics cards, but just fails on other.
If your primany use is gaming or normal Windows use then you will quite propably be
much happier with some commercial PC graphics card with TV output.

Note:
I got the system working nicely with Matrox Millenium and Windows 95.
With other graphics cards and operating systems it is hard to promise
anything, because the system relies very much on the driver
or other way to set the graphics card to a signal compatible
with the TV. All the cards/drivers can't do it or
the manufacturer does not tell how to do it.
If you have the hardware where the system is tested, then you should
get everythign working well, but if you have somehting else then

I can't promise anything that you get your system to work.
There are many people who have get this circuit working with some hacking
and also people who can't get this to work on their systems.
If you are running DOS or Linux then you have quite good changes
to get this work with some hacking. If you are using
any Windows version and any other the card for which I have
found this to work you are quite much out of luck.

Note2: The development of this circuit has has been quite much ended from
my side. I tried to get the drivers to be developed as free
use supported software (Like linux and GNU software), but that
did not seem to work too well, because not many people bothered to
send any detais back how did they get the system to work for
benefir the others. I have other projects to work with.
The main program is the software
support for various PC graphics cards, which I am not planning to do
(lack of time, resources and resource). This project is no longer largely supported
because supporting this will take too much time from me
too many questions coming all the time.
I don't send you any drives throug e-mail and
comment will this work on graphics card X on system Y running
operating system Z.. Read the documentation
and see what it says. If your graphics card is not mentioned in
the documentation then I can't help to detemine if it works with
this circuit or not. If you get the system work nicely a feedback
is wellcome.